public override string ToString()
{
StringBuilder sb;
List <string> r = new List <string>();
for (GStackElt e = tos; e != null; e = e.upper)
{
sb = new StringBuilder();
foreach (XType xt in e.xts)
{
if (sb.Length == 0)
{
sb.Append("<");
}
else
{
sb.Append(",");
}
sb.Append(xt.Name);
}
sb.Append(">");
r.Add(sb.ToString());
}
sb = new StringBuilder();
for (int n = r.Count - 1; n >= 0; n--)
{
if (sb.Length > 0)
{
sb.Append(" ");
}
sb.Append(r[n]);
}
return(sb.ToString());
}
/*
* This returns true if there is a combination of stack types
* that are sub-types of the types in xts[].
*/
internal bool MayMatch(XType[] xts)
{
if (xts.Length > Depth)
{
return(false);
}
int j = xts.Length - 1;
GStackElt e = tos;
for (;;)
{
bool found = false;
foreach (XType xt in e.xts)
{
if (xt.IsSubTypeOf(xts[j]))
{
found = true;
break;
}
}
if (!found)
{
return(false);
}
j--;
if (j < 0)
{
break;
}
e = e.upper;
}
return(true);
}
internal static GStack Make(XType[] topCombo, GStack tail)
{
GStackElt tos = tail.tos;
for (int i = topCombo.Length - 1; i >= 0; i--)
{
XTypeSet xts = new XTypeSet();
xts.Add(topCombo[i]);
tos = new GStackElt(tos, xts);
}
return(new GStack(tos));
}
internal GStackElt(GStackElt upper, XTypeSet xts)
{
this.upper = upper;
this.xts = xts;
if (upper == null)
{
rank = 0;
}
else
{
rank = upper.rank + 1;
}
}
static GStackElt MakeTOS(CCStack src)
{
if (src == null)
{
return(null);
}
GStackElt tos = null;
GStackElt r = null;
int num = 0;
IEnumerator <CCTypeSet> iter = src.EnumerateFromTop();
for (;;)
{
if (!iter.MoveNext())
{
break;
}
XTypeSet ss = new XTypeSet();
foreach (CCType ct in iter.Current)
{
ss.Add(ct.xType);
}
if (ss.Count == 0)
{
throw new Exception(string.Format("internal error: no element in CCStack at depth {0}", num));
}
GStackElt r2 = new GStackElt(null, ss);
if (r == null)
{
tos = r2;
}
else
{
r.upper = r2;
}
r = r2;
num++;
}
/*
* We assembled the GStack in reverse order, so all
* ranks are wrong and we must fix them.
*/
for (r = tos; r != null; r = r.upper)
{
r.rank = --num;
}
return(tos);
}
internal XTypeSet Peek(int depth)
{
if (depth > tos.rank)
{
throw new Exception("stack underflow");
}
GStackElt e = tos;
while (depth-- > 0)
{
e = e.upper;
}
return(e.xts);
}
GStack(GStackElt tos)
{
this.tos = tos;
}